You can refer to a situation as quicksand when you want to suggest that it is dangerous or difficult to escape from, or does not provide a strong basis for what you are doing.
例句
I was about to sink into the quicksand of sin...我就要陷入罪孽的深渊了。The research seemed founded on quicksand.这项研究犹如建在流沙之上,基础极不稳固。
英英词典释义
Noun
1. a treacherous situation that tends to entrap and destroy
2. a pit filled with loose wet sand into which objects are sucked down